compiz ( ccsm )
I select the lower section of Fixed Window Placement - Windows with Fixed Viewport.
Select New, then the Add (+) symbol.
Select a category - Window Class, Window Title, etc.
I find it easiest to already have the app I want to set up alread open so I can:
Hit 'Grab' and then click on the window you want to place. It will automatically fill in the proper info (Class, Title, etc). Hit Add again if you want to further specify the characteristics.
Set the X Viewport. I have 4 displayed in my workspace switcher, so I can set it to open in any one of the 4.
You can use the top part of the setup page (Windows with Fixed Positions) to place a window X pixels down and left from the top corner. For instance I only use one, to offset a window 75 down and 75 right.